Background: Cardiopulmonary bypass (CPB) affects coronary flow after the operation. Surgical as compared to device closure of atrial septal defect (ASD) serves as a good model to clarify the effects of surgery with CPB on coronary flow.
Methods: Coronary flow parameters were determined by transthoracic Doppler echocardiography before and after ASD closure. Thirteen children underwent surgery on CPB and fourteen children had device closure of their ASD under interventional cardiac catheterisation. Fourteen age-matched healthy controls were studied.
Results: Left ventricular fractional shortening increased and cardiac output increased after the device closure but there were no significant changes after the surgery. After the surgery the mean diameter of left anterior descending coronary artery increased from 1.7 +/- 0.6 to 2.1 +/- 0.4 mm (p = 0.03), the peak flow velocity in diastole (PFVd) from 48 +/- 10 to 70 +/- 12 cm/s (p = 0.0001) and basal blood flow (BF) from 62 +/- 18 to 105 +/- 35 ml/min (p = 0.0001). Flow parameters in the right coronary artery increased similarly. In contrast, all coronary flow parameters decreased substantially after catheter interventions, but still remained significantly elevated as compared with controls.
Conclusions: Surgery with cardiopulmonary bypass but not the device closure affects coronary flow beyond the pure effects of anatomical correction. Cardiac output increases after the device closure. The reported decrease of coronary flow reserve is obviously due to increased basal coronary flow.